[Henry] Arcing in 3K Premier tank circuit

[John Becker]

I'm looking for help trying to deal with a problem which shows up only 
on 12M on my 3K Premier. Unless I stay at quite low power, something 
arcs over in the tank circuit. Now that 12M is coming back to life in a 
big way, I need to solve this ASAP.

I know Henry made some significant changes in the tank circuit of the 3K 
Premier during the time it was produced, but they are not documented in 
the manual. I have pictures sent to me by different owners of three 
different versions.

On a very late production model, there is a mechanism to short out part 
of the rotary inductor on some bands. I recall reading somewhere that 
when a rotary inductor is at the low inductance end of its range, it can 
behave as an auto-transformer, inducing high voltage across the long 
unused and unterminated portion. I wonder if this is exactly what I'm 
experiencing and if this is the reason this change was implemented?

Any suggestions or additional information would be appreciated. Thanks!

73,

John, K9MM